To enhance efficiency and reduce cost, replacing the traditional DC castingCasting and hot rolling process with the twin-roll castingCasting process for producing 80218021 aluminum alloyAluminum alloy has become a research focus on aluminum foilAluminum foil production. This paper investigates the effects of castingCasting thickness and the addition of Al-Ti-B wire on the microstructureMicrostructure, second phases, and mechanical propertiesMechanical properties of twin-roll castingCasting 80218021 aluminum alloyAluminum alloy sheets. The results show that the castingCasting thickness has a weak effect on the grain size of the sheets, but a higher Ti content dramatically refines the microstructuresMicrostructure and improves their uniformityUniformity. Al3Fe is the predominant second phase, which transforms into Al(Fe,Mn)Si, α-AlFeSi, and β-AlFeSi during cooling. At the same thickness, the increase of Ti content refines the grain size but has no significant effect on the tensile strengthTensile strength. On the contrary, the increasing Ti content significantly improves the elongation of the sheets by 9.55% and 15.17% for 6.2 mm and 9.0 mm sheets, respectively. The elongation reaches the maximum as the Ti content is 0.026% and the castingCasting thickness is 9.0 mm. The findings can provide valuable guidance for the process design of subsequent homogenization annealingHomogenization annealing, cold rolling, and final annealingAnnealing.